Not one of that size...
There actually aren't any more stadia of sufficient size...
The RDS in Dubiln holds about 20,000 for concerts.
Thomond Park in Limerick holds 25,000.
Pairc ui Caoimh in Cork holds 32,000.
The Gaelic Grounds in Limerick can apparently hold 49,000 but I've never heard of a concert there... it's probably got a lot of standing area in the stands...?
Similar story with Semple Stadium, Tipperary - 53,000.
The Aviva Stadium in Dubiln holds 52,000.
Croke Park holds 85,000.
So, 2 nights at any of the 3 largest alternate venues above would give you slightly more attendees, but I'm guessing it's not enough of an increase to make it financially worthwhile given the extra cost of an added date.
Of course, they could do one night in Croker and one night somewhere else...